Sea weeds come under polyphyletic group of the phylogeny.
What is phylogeny?
Phylogeny is the study of a species' or group's evolutionary history, particularly as it relates to relationships and lines of descent among large groups of animals.
The idea that distinct species of plants or animals descended from a single ancestor is fundamental to phylogeny and is widely recognized in the scientific community. Since the majority of animals that have ever existed are extinct and only a small portion of their fossilized remnants have been preserved in the fossil record, the evidence for these relationships is almost always insufficient. Therefore, the majority of phylogenies are based on inferential data and are hypotheses. Commonly, different phylogenies can be inferred from the same evidence.
Learn more about the phylogeny with the help of the given link:-
